The Core B (Microscopy and Molecular Histology) laboratory provides services not only in routine microscopic techniques such as tissue preparation and analysis by light and electron microscopy for Program Project investigators, but it also serves as a large scale resource for contemporary analytical morphological methods, including immunohistochemistry, immuno-electron microscopy, isotopic and non-isotopic in situ hybridization, and digital imaging technology, including quantitative analysis of microscopic images, and generation of composite images and slides using computer imaging tools. Furthermore, the Morphology Core interfaces and interacts with the VAMC Confocal Microscopy Facility, preparing samples for immuno-histochemical and immunolocalization analysis. The Microscopy and Molecular Histology Laboratory also teaches and trains large numbers of technicians, undergraduate and graduate students, research associates, visiting fellows and residents, who are working on different Program Project-related studies. The Core B facility of consists of two physically-separate suites of laboratories, with a total area of 1400 ft[2] (600ft[2] + 800ft[2]), where separate modules are dedicated to experimental procedures and tissue collection, tissue fixation and processing (dehydration, embedding, resin polymerization, etc.), histology (frozen and paraffin sectioning), ultramicrotomy, cryoultramicrotomy, microscopy (light, fluorescence, digital, and electron microscopy), and darkroom work. The personnel of Core B are Peter M. Elias, M.D., Director, Debra Crumrine, and Sandra Chang, Technicians. The Microscopy and Molecular Histology Laboratory not only provides service for program project investigators, but its Director is also involved actively in the planning of experiments and in the analysis and interpretation of investigators' data. The Microscopy and Molecular Histology Laboratory is committed to improving traditional morphological methods; to introducing newly developed techniques; and to devising novel methods for studying the biology of keratinocytes and the skin. Against this background, the Microscopy and Molecular Histology Laboratory will continue to advise and assist Program Project investigators with their microscopic and morphological studies, as required.